Abstract
The aim of this work is to verify the possibility of improvement of the impact strength in a state quenched and tempered + QT at -40 ° C depending on the finish-rolling temperature with controlled cooling. The theoretical section describes the controlled thermal forming, healing processes in the structure, influence of some micro-alloying elements on the notch toughness tests and description of the Charpy impact test method. The practical and experimental section acquaints us with basic information about the computer program KJTRoll, experimental analysis of the problem and the light section rolling line in TŽ a.s. The last section is the ASV evaluation of the measured values of impact and mechanical properties at different finish-rolling temperatures.